Electrical heating element assembly

Abstract

An insulator for an electrical heating element includes an inner section and an outer section removably disposed thereabout. The electrical heating element is removably and loosely received within at least one of the sections. Several of these insulators can be used to make a new and improved electrical heating element assembly.

What is claimed is: 
     
       1. An electrical heating element assembly, comprising a plurality of electrical heating means extending axially along said assembly; a plurality of electrical insulators spaced apart axially along said assembly, each of said insulators including an inner section having an outer peripheral edge, an outer section disposed about and adjacent to said inner section and having an inner peripheral edge, receiving means provided in one of said peripheral edges for removeably receiving said plurality of electrical heating means, said receiving means including a plurality of slots, each of said slots extending axially through said one peripheral edge and being sized and shaped such that a corresponding one of said electrical heating means extends loosely and moveably therethrough without making substantial contact with either of said sections, whereby the natural expansion and contraction of said electrical heating means are substantially uninhibited by said insulators during the electrical energization and de-energization thereof, and securing means for releaseably securing said inner section to said outer section such that when said inner and outer sections are secured to each other they cooperate to completely surround each of said electrical heating means, whereby each of said insulators electrically insulates each of said electrical heating means from the other of said electrical heating means, and such that when said inner and outer sections are not secured to each other said electrical heating means may be radially withdrawn from said slots, whereby said electrical heating means can be removed from said insulators and replaced without completely disassembling said electrical heating element assembly; a plurality of spacers, each of said spacers being interposed between a corresponding pair of insulators; retaining means for retaining each of said insulators between a corresponding pair of adjacent spacers; and supporting means for supporting said electrical heating means, said supporting means supporting said electrical heating means substantially independently of said insulators at least when said electrical heating element assembly is arranged vertically. 
     
     
       2. In combination, a radiant tube and an electrical heating element assembly positioned within said radiant tube, said electrical heating element assembly including a plurality of electrical heating means extending axially along said assembly; a plurality of electrical insulators spaced apart axially along said assembly, each of said insulators including an inner section having an outer peripheral edge, an outer section disposed about and adjacent to said inner section and having an inner peripheral edge, receiving means provided in one of said peripheral edges for removeably receiving said plurality of electrical heating means, said receiving means including a plurality of slots, each of said slots extending axially through said one peripheral edge and being sized and shaped such that a corresponding one of said electrical heating means extends loosely and moveably therethrough without making substantial contact with said either of said sections, whereby the natural expansion and contraction of said electrical heating means are substantially uninhibited by said insulators during the electrical energization and de-energization thereof, and securing means for releaseably securing said inner section to said outer section such that when said inner and outer sections are secured to each other they cooperate to completely surround each of said electrical heating means, whereby each of said insulators electrically insulates each of said electrical heating means from the other of said electrical heating means, and such that when said inner and outer sections are not secured to each other said electrical heating means may be radially withdrawn from said slots, whereby said electrical heating means can be removed from said insulators and replaced without completely disassembling said electrical heating element assembly; a plurality of spacers, each of said spacers being interposed between a corresponding pair of insulators; retaining means for retaining each of said insulators between a corresponding pair of adjacent spacers; and supporting means for supporting said electrical heating means, said supporting means supporting said electrical heating means substantially independently of said insulators at least when said electrical heating element assembly is arranged vertically. 
     
     
       3. Apparatus according to claim 1 or 2, wherein said slots of each of said insulators are formed primarily in said inner section of each of said insulators. 
     
     
       4. Apparatus according to claim 1 or 2, wherein said slots of each of said insulators are formed primarily in said outer section of each of said insulators. 
     
     
       5. Apparatus according to claim 1 or 2, wherein each of said electrical heating means has a predetermined width and a predetermined thickness and each of said slots of each of said insulators has a predetermined width and a predetermined length, said predetermined width of said slots being greater than said predetermined thickness of said electrical heating means and said predetermined length of said slots being greater than said predetermined width of said electrical heating means. 
     
     
       6. Apparatus according to claim 1 or 2, wherein said outer section of each of said insulators includes a retaining ring. 
     
     
       7. Apparatus according to claim 6, wherein each of said retaining rings includes a plurality of arcuate segments arranged end to end. 
     
     
       8. Apparatus according to claim 6, wherein each of said retaining rings has an outer circumferential edge and an annular recess formed in said outer circumferential edge thereof and each of said securing means includes a piece of wire wrapped around said outer circumferential edge of a corresponding one of said retaining rings and seated in said annular recess of said corresponding one of said retaining rings. 
     
     
       9. Apparatus according to claim 8, wherein each of said securing means includes a plurality of wire loops, each loop extending generally radially outwardly from said inner section of a corresponding one of said insulators and being sized and shaped such that said retaining ring of said corresponding one of said insulators passes therethrough in close proximity thereto. 
     
     
       10. Apparatus according to claim 1 or 2, wherein each of said insulators includes fixing means for fixing the axial position of said outer section of a corresponding one of said insulators relative to said inner section of said corresponding one of said insulators. 
     
     
       11. Apparatus according to claim 10, wherein each of said fixing means includes a tongue and groove joint, including a tongue provided on one of said peripheral edges of a corresponding one of said insulators and a groove provided in the other of said peripheral edges of said corresponding one of said insulators. 
     
     
       12. Apparatus according to claim 11, wherein each of said tongues is provided on said outer peripheral edge of said inner section of a corresponding one of said insulators and said groove is formed in said inner peripheral edge of said outer section of said corresponding one of said insulators. 
     
     
       13. Apparatus according to claim 1 or 2, wherein each of said insulators includes a generally centrally located bore passing axially therethrough. 
     
     
       14. Apparatus according to claim 13, wherein each of said spacers has a central bore in communication with said bores of a corresponding pair of adjacent insulators. 
     
     
       15. Apparatus according to claim 14, wherein said retaining means includes a metal rod passing through said bore of said insulators and said bores of said spacers. 
     
     
       16. Apparatus according to claim 1 or 2, wherein each of said heating means is one leg of a heavy gauge metal alloy strip bent into a serpentine pattern. 
     
     
       17. Apparatus according to claim 16, wherein said supporting means includes a pair of terminal posts, each of which connects said strip to a source of electrical energy.